Calculator inputs
Use the responsive grid below. It shows three columns on large screens, two on medium screens, and one on mobile.
Formula used
This calculator focuses on turbidity removal, hydraulic production, and chemical use. NTU is an optical indicator, so the load term below is a process proxy rather than a direct solids mass balance.
NTU Removed = Raw Turbidity - Treated Turbidity
Removal Efficiency (%) = ((Raw Turbidity - Treated Turbidity) / Raw Turbidity) × 100
Reduction Factor = Raw Turbidity / Treated Turbidity
Gross Treated Volume (m³) = Flow Rate (m³/h) × Run Time (h)
Net Delivered Volume (m³) = Gross Treated Volume × (1 - Backwash Loss / 100)
Coagulant Used (kg) = Coagulant Dose (mg/L) × Net Delivered Volume (m³) / 1000
Target Deviation (NTU) = Treated Turbidity - Target Turbidity
Performance Index = Removal Efficiency / Coagulant Dose
Design Effluent (NTU) = Treated Turbidity × (1 + Safety Factor / 100)
Turbidity Load Proxy (NTU·m³) = NTU Removed × Net Delivered Volume
How to use this calculator
- Enter the measured raw water turbidity and treated water turbidity in NTU.
- Add your target turbidity to check whether the process meets the desired finish.
- Provide flow rate and run time to estimate gross production and net delivered volume.
- Enter coagulant dose and backwash loss to evaluate chemical demand and effective recovery.
- Use the safety factor to test a conservative design or operational margin.
- Click the calculate button. The results appear above the form and below the header, with CSV and PDF export options.
Example data table
These sample runs illustrate how the calculator interprets different treatment conditions.
| Run | Raw NTU | Treated NTU | Target NTU | Flow m³/h | Hours | Dose mg/L | Loss % | Removal % | Net Volume m³ | Chemical kg | Meets Target |
|---|---|---|---|---|---|---|---|---|---|---|---|
| A | 120.0 | 1.8 | 1.0 | 45 | 8 | 32 | 4 | 98.50 | 345.60 | 11.06 | No |
| B | 80.0 | 0.6 | 0.8 | 30 | 10 | 24 | 3 | 99.25 | 291.00 | 6.98 | Yes |
| C | 45.0 | 2.2 | 1.5 | 18 | 12 | 18 | 5 | 95.11 | 205.20 | 3.69 | No |
| D | 250.0 | 0.9 | 1.0 | 60 | 6 | 40 | 6 | 99.64 | 338.40 | 13.54 | Yes |
Frequently asked questions
1. What does turbidity removal mean?
Turbidity removal measures how much cloudiness is reduced during treatment. It compares raw and treated water readings, then expresses improvement as NTU reduction and percentage efficiency.
2. Why is treated turbidity sometimes higher than expected?
Poor coagulation, short flocculation time, filter breakthrough, sampling timing, or instrument error can raise treated turbidity. Recheck pH, dose, mixing intensity, and maintenance records.
3. Does this calculator estimate solids mass removed?
No. NTU is an optical indicator, not a direct mass concentration. The turbidity load proxy is useful for comparison, but it does not replace lab-based solids testing.
4. Why is coagulant use based on net volume?
Using net delivered volume gives a practical view of chemical demand relative to usable treated water. It helps compare operational efficiency after recovery losses are considered.
5. What is the reduction factor?
The reduction factor shows how many times lower the treated turbidity is than the raw turbidity. Higher values indicate stronger clarification or filtration performance.
6. How should I choose the target turbidity?
Choose the target from plant design criteria, internal quality goals, or regulatory guidance. Many systems use very low finished-water values, especially before disinfection.
7. What does the safety factor do?
The safety factor inflates treated turbidity to create a conservative design check. It shows whether performance still meets the target when a chosen operating margin is applied.
8. When should I export the results?
Export results when documenting jar tests, comparing filter runs, reviewing production losses, or sharing treatment performance during design studies and operational meetings.